Why do we set a particular age as the age we're able to legally consent to or engage in sexual activity? What are the intentions or purposes of that particular law? Where should it be set to/how old? And are these laws effective at achieving the intended purposes?

Japan's is set at 12 and they're famous for having lowest rates of sexually related behavioural and social issues in regards to young people and children, such as abuse or rape in the world. Other more sexually active countries also have theirs set at 12. Focus on the 3 points, please.

Some countries (or States) have theirs set at age 21, and they're not far from having the world's worst child abuse, pregnancy and sexual health stats.. So why is it?

1) Japan was a bad example, because they are now more concerned about low age birth rates and there are many more rapists in japan then in the U.S (if that is what your implying).

2) The younger you have sex and birth, the more your health is in danger. Why places have their age set at 21 years old is because by then your sexual organs are fully developed. This lowers the chance of disease and death.

Japan's age of consent is actually 13 years old and that shows if you look up basically any anime from Japan and see how sexualized the characters are like, and I don't want to admit this but I have watched Sailor Moons and I was curious so I looked up their ages and Sailor Moon herself was 14 years old.

The age of consent is a way to protect young teenagers from abusers. How low should it be? The avarage is 14 years old, which is a reasonable age since all women get phisically developed at this age. More than this seems to be counterproductive, illogical, and unreal.

Japan was a terrible choice of an example. Their government is concerned about low birth rates. Japanese people are having sex at an all time low. It is so low that the government of Japan is, for the first time ever, easing it's migration laws so it can stabilize the population and fill jobs. Their males are feminized and their girls wear bunny ears. Using their statistics to make a point about age of consent totally misses the mark.